When baker's dough is mixed it is usually blended in a large mixer wherein the batch of dough developed in the mixer has a density of approximately 69 lbs. per cubic foot. The dough must then be transferred from the mixer to a stuffing pump whereupon the stuffing pump progressively pressurizes the batch of dough to form the dough into a stream that moves through conduits to subsequent dough handling equipment, such as a metering pump, a dough distribution manifold which distributes the stream of dough into multiple streams of dough, a dough divider which divides the streams of dough into globs of dough of equal weight, and onto a surface conveyor of a rounder bar system which forms the globs of dough into substantially rounded dough balls with a slightly developed skin which resists sticking to the down stream processing equipment.
Once the dough has been mixed, the dough begins to develop CO.sub.2 and it expands or "rises" as it ages. As the dough is being handled by the prior art stuffing pumps and subsequent processing equipment leading to the dough divider, the dough is sheared, torn, stretched, held at elevated pressures and otherwise handled in a manner that tends to deteriorate the gluten structure of the dough. Maintaining a pliable gluten structure is important in providing a final product which has uniform grain structure since the gluten structure provides the walls of the small pockets that trap the CO.sub.2 gas being formed which in turn provides the tight even grain structure desired for sliced bread and buns. Therefore, it is desirable in the handling of the stream of pressurized dough that the dough not be unnecessarily stretched, torn or sheared and held at elevated pressures.
Preferably, the stream of pressurized dough should pass through as few constrictions and changes of direction as is practical so as to avoid tearing, stretching and shearing and to avoid the requirement of high pressure to transport the dough and to avoid large pressure drops. Further, it is desirable to maintain the dough under high pressure for as short a period of time as is practical so as to avoid deterioration of the gluten structure.
A common practice for subdividing a stream of baker's dough moved by the stuffing pump of a dough handling system has been to move the stream of dough into a common manifold and exhaust the dough from several outlet ports of the manifold into separate conduits and to deliver the dough from the several conduits to a dough divider that continually slices each subdivided stream of dough into dough balls. One of the major problems with the prior art systems is the accurate control of the dough as it moves through the manifold and to the dough divider. It is important that the dough be delivered through each conduit to the dough divider at substantially equal masses for a given time period so that when the streams of dough are separated into dough balls by the dough divider, each dough ball will be of a predetermined mass that is suitable for subsequent rounding, proofing and baking to yield baked products all of which are of uniform size, shape, consistency and weight.
The method practiced by the prior art generally comprises the installation of valves in each conduit leading away from the dough distribution manifold toward the dough divider. When the operator of the system detects too much or too little dough moving through one of the conduits, the valve for that conduit is adjusted to adjust the dough flow through the conduit.
For example, when a valve is moved more toward its closed position to further constrict the passage of the conduit, the rate of dough moving from the manifold through the valve to the divider decreases and the back pressure of the dough stream leading toward the valve increases, which leads to increased back pressure in the distribution manifold and in the adjacent valves of the other discharge conduits. Usually, this causes an increased flow through the adjacent conduits but not through the remote conduits. Therefore, in order to adjust the flow of dough through one conduit, the system operator usually is required to adjust the valves of at least the adjacent conduits, and possibly other valves of the distribution system. Further, the presence of so many valves to control the system increases the constrictions in the flow paths of the dough and, therefore, increases the amount of pressure required to drive the system. Further, the placement of valves in each delivery conduit where the cross section of the dough is relatively small generally functions to cause a relatively high pressure drop across the valve, thereby requiring increased back pressure to force the dough past all the valves, and comprising a constriction in each dough path that causes the dough to change shape and direction of movement.
An example of a prior art dough stream control system is found in U.S. Pat. No. 4,948,611 which teaches that each of the dough streams be fine tuned by means of throttling valves in each delivery conduit.
In addition, the typical prior art dough distribution manifolds require the dough, and therefore the gluten strands that are interconnected throughout the dough mass, to be torn apart as the dough is divided from the inlet stream into several outlet streams to the dough divider. The tearing of the gluten strands causes deterioration of the gluten strands at the point of rupture as well as requiring greater back pressure to provide the energy to tear the strands. The higher required pressures cause the gluten to age rapidly and increases the dough temperature, the first result causing a deterioration of final product quality and the second making it more difficult to "machine" (round, shape and mold) the final dough ball.
Further, it is important that all of the dough in the final product proceed through a uniform environment during dough processing, proofing and baking phases. As shown by the cited prior patent, the prior art dough distribution manifolds require the dough to proceed different distances from the entrance of the manifold in different directions to the outlets of the manifold, and along conduits of differing lengths and varying back pressures and varying residence times to reach the dough divider. The result is a significant variation in product from the outlets of the different conduits.
Therefore, it can be seen that it would be desirable to provide a distribution system for baker's dough that separates the stream of dough leading from the stuffing pump toward the dough divider into a plurality of dough streams that are of equal mass and velocity and with lower driving pressure and lower pressure drop of the dough as the dough moves through the system.